Technical Abstract:
This book chapter provides a review of biological control agents used to suppress insect pests of stored grain and food processing facilities. Biological control has several advantages compared to chemical insecticides. Natural enemies leave no harmful chemical residues; and after release in a storage facility, many natural enemies continue to reproduce as long as hosts are available and environmental conditions are suitable. Unlike chemicals that need to be applied to a wide area, natural enemies can be released at a single location, and they will find and attack pests located deep inside crevices or within a grain mass. There are many types of organisms that can be used for stored-product insect control, such as insect predators, insect parasitoids, and various viral, bacterial or fungal insect pathogens. In stored grain, beetles are frequently the primary insect problem. Biological control has been most effective when insect parasitoids have been used to suppress these pests in stored grain. Mills and bakeries harbor a wide variety of stored-product pests with many of the same insect species found in bulk grain storage. In this type of environment, moths and flour beetles are the primary concern. Both egg and larval parasitoids as well as predatory mites have been used for the management of stored-product moths in the above situations. Trichogramma wasps have been used to suppress moth outbreaks in mills and retail stores in Germany. Successful biological control of insect pests in mills, bakeries, warehouses, and retail stores will require that the pest-control manager have a good understanding of the pest population dynamics in each facility. The release of parasitoids in a biological control program needs to be integrated with pest monitoring and sanitation programs. We must not expect that biological control agents should be able to control pests without the use of other methods. While biological control may not be compatible with all traditional chemical insecticides, a variety of other methods may prove to be compatible. An effective sanitation program, aeration, heat treatments, fumigants, insect-resistant packaging, and selective insecticides (such as Bacillus thuringiensis) could be used with biological control as part of a broader IPM program. Hygienic and sanitary measures in storage are a prerequisite to effective biological control because natural enemies have been shown to be most effective at low pest densities. Biological control will play an increasingly important role in protecting stored products from insect infestation. The growing level of government and consumer concern over insecticide residues in food have led to reduced availability of traditional chemical insecticides. This has increased the importance of alternative methods, such as biological control, in stored-product insect pest management.